This invention relates to a vehicle steering column and in particular to means to absorb energy transmitted through a steering column in the event of a vehicle crash and/or driver impact on a steering wheel.
In many steering columns, a steering wheel lock is press fitted onto the end of an outer tube of the steering column and in use the steering lock engages with a series of castalations on the steering wheel to lock it.
A known problem has been of how to absorb chest impact energies of a driver in a vehicle which has a rake/reach or tilting steering column. Existing constructions include crushing or extending a convoluted tube, which have the problem of relatively high tool cost and low natural frequency. Other known constructions tend to move the energy absorbing mechanism away from the driver and/or involve additional components.
Energy imparted by the driver on the steering wheel in the event of impact is transmitted from the steering wheel down the steering column. With an adjustable steering column, it will be appreciated that the steering column can be moved up and down and in and out relative to supporting bracketry remote from the steering wheel and this prevents the use of a fixed energy absorbing portion between the steering wheel and supporting bracketry.
The foregoing illustrates limitations known to exist in present steering column energy absorbing mechanisms. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.